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2. 发明专利

GB190212965A Improvements in Drawing Boards, Squares and Protractors. 未知
公开(公告)号：GB190212965A
公开(公告)日：1903-05-07
申请号：GB190212965D
申请日：1902-06-06
申请人： LOW DAVID ALLAN
发明人： LOW DAVID ALLAN
摘要： 12,965. Low, D. A. June 6. Squares.-T-squares and fixed and adjustable set-squares are preferably made with the drawing- edges raised slightly from the paper &c., to prevent smudging when inking-in. For this purpose, the squares may be formed with continuous ridges or corrugations, or with series of isolated prominences, and by thus reducing the area of contact, the paper is not soiled to the same extent as when flat squares are used. Framework set-squares are jointed as represented in Figs. 9 and 12. In Fig. 9, short saw slits are made in the adjacent sides in the direction of the grain of the wood, and are filled by a V-shaped piece 4 of brass or mild steel/provided with projections 5 to be bent down flush with the surface of the wood. In Fig. 12, the set-square is made up of a middle layer w of wood, celluloid, &c. and outer layers c, f of celluloid. When the middle layer is of wood, the three strips are glued or cemented together at the mitre joints, and when of celluloid, these strips may be used, or the layer may be in one piece. The outer celluloid surfaces prevent soiling of the paper, and may be of slightly-less size than the middle layer, to form a raised working-edge. The middle layer, if of wood, may be edged with celluloid or ebony &c., and the outer layers then overlap and are cemented to the edges. Strips of celluloid may be inserted :n edged middle layers to obtain a better fastening for the outer celluloid layers, and for the same purpose short pieces of celluloid may be inserted in saw-cuts at the mitre joints of wood middle layers. An adjustable setsquare is shown in. Fig. 16. The blade b is hinged between two large, thin; metal plates or discs m, which are fixed to the other part of the square, or one of the plates may be a projection from the other part of the square. The plates m are recessed into the wood, and, in the case of a framework square, serve to bind the two fixed arms by the aid of rivets r. A tubular rivet t secures the parts b, m together. An adjustable set-square and protractor combined is shown in Fig. 18, and is conveniently made of three layers of wood and celluloid as described above. The square S is made with the third side shaped to a concave circular arc, to which a segmental piece p is fitted by a continuous groove-and-tongue joint formed by extending the layers or by celluloid additions. T-square blades may be formed of thin steel &c., with a raised working-edge and bearing prominences, and the back edge may be flanged to retain pencils, pens, &c. and to increase the stiffness of the blade. The blade may be further stiffened by one or more longitudinal corrugations. The blade may be made of three layers of wood and celluloid as described above. The stock may be made of thin steel &c. and flanged or provided with tubular edges.

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